EV Battery Assembly Voltage Balancing via DC/DC Converter
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Solution Overview
Problem
Electric vehicles with swappable battery units experience varying driving performance due to differing states of charge and output voltages, which can be undesirable for drivers.
Innovation Solution
A battery assembly with a first battery unit, a DC/DC converter, and a battery receptacle for a second battery unit, where the DC/DC converter balances differing states of charge and output voltages, and a control unit to selectively enable connections for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a second swappable battery unit is used to increase driving range, then the driving range is extended, but the driving performance varies due to differing states of charge and output voltages
Solution Approach 1:
The DC/DC converter serves as an intermediary device between the first and second battery units. It actively balances the output voltages of the two battery units through controlled current transfer, ensuring that both batteries operate at compatible voltage levels. This mediation eliminates the performance variation caused by different states of charge and voltage levels, while still allowing the second battery to extend the driving range.
2Power
If the second battery unit is connected directly to the inverter unit, then the driving performance is enhanced by bypassing the DC/DC converter, but the ability to balance voltage and charge differences is lost
Solution Approach 1:
The system dynamically switches between two connection configurations: (1) direct connection of the second battery to the inverter for high-power performance, and (2) connection through the DC/DC converter for voltage balancing. The control unit monitors battery states and automatically selects the appropriate configuration, allowing the system to adapt its topology based on operational requirements rather than being fixed in one mode.
Solution Approach 2:
The electric connection system is segmented into multiple independent pathways: a direct connection path from the second battery to the inverter, and a balanced connection path through the DC/DC converter. This segmentation allows each pathway to serve its specific function optimally - direct connection for power delivery and converter connection for voltage equalization - without interfering with the other.
3Adaptability or versatility
If the first battery unit and second battery unit have different states of charge and output voltages, then flexibility in battery selection is maintained, but the driving performance varies
Solution Approach 1:
The control unit continuously monitors the states of charge and output voltages of both battery units, and based on this feedback, actively controls the DC/DC converter to balance the voltages before operation. This feedback mechanism allows the system to maintain flexibility in battery selection while ensuring consistent driving performance by correcting voltage imbalances in real-time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides consistent and enhanced driving performance by balancing voltage and charge differences between battery units, allowing for flexible and efficient energy use.
Implementation Method 1
a DC/DC converter, which is configured for transforming a direct current (DC) of a first voltage into a direct current of a second voltage
Data Source
AI summary
A battery assembly for an electric vehicle including a first battery unit, a DC/DC converter, and a battery receptacle for selectively receiving a second battery unit. The first battery unit is electrically connected to the DC/DC converter. Moreover, a first electric connection interface is positioned in the battery receptacle and is electrically connected to the DC/DC converter. Additionally, a vehicle including such a battery assembly is presented. Furthermore, a method for operating an electric vehicle is explained. A first operational mode includes electrically connecting the first battery unit to an electric traction machine and electrically connecting the second battery unit to the first battery unit. A second operational mode includes electrically connecting the second battery unit to the electric traction machine.